This invention is generally directed to conductive composite particles and processes for the preparation thereof, and more specifically, the present invention relates to processes for the preparation of conductive polymeric composite particles, comprised of polymer and conductive component, or filler distributed, preferably evenly throughout the polymer matrix of the composite, and which component is preferably carbon black. In embodiments, the process of the present invention comprises the preparation of conductive polymeric particles containing a conductive filler distributed substantially throughout the polymer matrix of the particles, and which particles can be selected as carrier powder coatings, and a process which comprises the preparation of conductive polymeric composite particles with a volume average particle size diameter of from between about 0.05 micron to about 5 microns, and preferably from about 1 to about 5 microns, and which size can be determined by, for example, a Coulter Counter. The conductivity of the generated polymeric composite particles can be modified by, for example, varying the weight percent of conductive filler component present in effective amounts of, for example, from between about 1 weight percent to about 50 weight percent, and also by varying the composition of the conductive filler component. Thus, in embodiments conductive submicron polymeric composite particles with a conductivity of from between about 10.sup.-10 (ohm-cm).sup.-1 to about 0.10 (ohm-cm).sup.-1 can be prepared. In embodiments, particles with average diameter of about 0.05 to about 5 microns are conductive composite particles which are comprised of polymer and a conductive filler distributed evenly throughout the polymer matrix of the composite product, and which product can be obtained by a modified polymerization method in which at least one monomer is mixed with a conductive filler, solvent, one or more polymerization initiators, and an optional chain transfer component; effecting solution polymerization by heating until from about 80 to about 100 weight percent of the monomer has been polymerized; removing and recovering the solvent using an azeotropic distillation process in an aqueous phase, then filtering off the aqueous phase, and subsequently drying and grinding the resulting polymer and conductive filler bead product; dispersing the aforementioned mixture of conductive filler or fillers and polymer in at least one monomer with one or more polymerization initiators, a crosslinking agent and an optional chain transfer agent; dispersing the resulting mixture in water containing a stabilizing component, such as polyvinyl alcohol, to obtain a suspension of particles with an average diameter of from about 0.05 to about 5 microns in water; polymerizing the resulting suspension by heating; and washing the product and then drying; and wherein there is selected an azeotropic distillation, and wherein an alkali iodide, such as potassium iodide is added to the aqueous phase prior to particle formation, and wherein there is preferably selected a continuous inline homogenizer.
Metals such as carrier cores are conductive or semiconductive materials, and the polymeric materials used to coat the surface of metals are usually insulating. Therefore, carrier particles coated completely with polymer or a mixture of polymers can lose their conductivity and become insulating. Although this is desired in some situations, for conductive magnetic brush systems (CMB) the carrier particles should primarily be conductive. Since the carrier polymer coating can be utilized to primarily control carrier tribo, an economical conductive carrier coating process is needed to generate carriers with the desired conductivity and triboelectric properties. Also, conductive polymers are costly, and are not considered suitable for preparing low cost, for example less than $5/pound, coatings, thus a conductive polymer process is needed wherein a low cost polymer and a conductive filler, such as conductive carbon black, are selected.